The goal of the Cell Biology Core is to provide investigators in all the projects with preparations of cardiac myocytes for their work. As described in the Research Plans, cardiac myocytes will be used in a variety of experimental protocols from electrophysiology, where acutely dissociated cells are used, to 'molecular physiology' with viral-mediated gene transfer, which demands preparations of cultured cardiac myocytes. Considerable expertise exists within the PPG as all of the Project Leaders are experienced with a diverse range of cardiac myocyte preparations. However, we have found in the past, during our collaborative efforts, that considerable inefficiency exists in the preparation and use of cells. For example, different groups may be preparing acutely dissociated cells on the same day that could have been shared. One group might invest time establishing a new preparation, for example, of cultured neonatal mouse cells, only to find that another group has prepared them for months. Thus, this Core will streamline the production and use of cardiac cells for all the projects in this PPG by centralizing the expertise and functioning as a 'centralized warehouse.' Thus, this Core will provide a framework of enhanced communication and organization that will result in a major cost savings for all of the projects. NOTE: The Core will be responsible for the ordering and maintenance of normal mice and rats that will be used in the preparation of normal cells. Each project in the program will be responsible for the maintenance of specialized transgenic animals. Thus, costs associated with such animals are included in the budget of individual projects. The Core can provide expertise in the preparation of isolated cells from diseased hearts as warranted. (End of Abstract)